From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wu Fengguang Subject: Re: [PATCH 4/4] writeback: Reporting dirty thresholds in /proc/vmstat Date: Tue, 24 Aug 2010 10:11:36 +0800 Message-ID: <20100824021136.GA9254@localhost> References: <20100821054808.GA29869@localhost> <20100824100943.F3B6.A69D9226@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: KOSAKI Motohiro , Peter Zijlstra , "linux-kernel@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "linux-mm@kvack.org" , "jack@suse.cz" , "riel@redhat.com" , "akpm@linux-foundation.org" , "david@fromorbit.com" , "npiggin@kernel.dk" , "hch@lst.de" , "axboe@kernel.dk" To: Michael Rubin Return-path: Received: from mga11.intel.com ([192.55.52.93]:44190 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754175Ab0HXCLk (ORCPT ); Mon, 23 Aug 2010 22:11:40 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-ID: > Right now we don't mount all of debugfs at boot time. We have not done > the work to verify its safe in our environment. It's mostly a nit. You work discreetly, that's a good thing. Note that most sub-directories under debugfs can be turned off in kconfig. > Also I was under the impression that debugfs was intended more for > kernel devs while /proc and /sys was intended for application > developers. I guess the keyword here is "debugging/diagnosing". Think about /debug/tracing. DirtyThresh seems like the same stuff. > >> 3) Full system counters are easier to handle the juggling of removable > >> storage where these numbers will appear and disappear due to being > >> dynamic. > > This is the biggie to me. The idea is to get a complete view of the > system's writeback behaviour over time. With systems with hot plug > devices, or many many drives collecting that view gets difficult. Sorry for giving a wrong example. Hope this one is better: $ cat /debug/bdi/default/stats [...] DirtyThresh: 1838904 kB BackgroundThresh: 919452 kB [...] It's a trick to avoid messing with real devices :) Thanks, Fengguang